We found this black walnut shell on our driveway. Someone must have tossed it out since there are no walnut trees anywhere in our neighborhood. On the one hand, I can see both a heart and a face in this little guy. At the same time, I also feel a little menace emanating from those two deep holes. It turns out that black walnut trees can be toxic to certain plants and that the range of the toxicity extends outward as the tree grows.